Case-sensitive excludedSubtrees name constraints cause Auth Bypass in crypto/x509
When verifying a certificate chain containing excluded DNS constraints, these constraints are not correctly applied to wildcard DNS SANs which use a different case than the constraint. This only affects validation of otherwise trusted certificate chains, issued by a root CA in the VerifyOptions.Roots CertPool, or in the system certificate pool.
01
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-33810US | high8.2 | — | ||
When verifying a certificate chain containing excluded DNS constraints, these constraints are not correctly applied to wildcard DNS SANs which use a different case than the constra… | ||||
02
references
External citations — patches, advisories, analysis.
- http://www.openwall.com/lists/oss-security/2026/04/19/4WEB
- http://www.openwall.com/lists/oss-security/2026/04/20/1WEB
- https://access.redhat.com/errata/RHSA-2026:10155WEB
- https://access.redhat.com/errata/RHSA-2026:10158WEB
- https://access.redhat.com/errata/RHSA-2026:13545WEB
- https://access.redhat.com/errata/RHSA-2026:14391WEB
- https://access.redhat.com/errata/RHSA-2026:19135WEB
- https://access.redhat.com/errata/RHSA-2026:19144WEB
scry
Advisories like this name the exposed products attackers go after on your perimeter. See what is exposed on your perimeter with a free passive scan.
Free scan